This invention relates to the field of food processing, and more particularly, to apparatus and methods for peeling vegetables and fruits.
It is common in many food processing applications to require the peeling of the outer skin of fruits or vegetables. Potatoes, in particular, are very often so processed by passing the potatoes against a set of rotating abrasive rollers. Fruit may also be similarly processed. For example, U.S. Pat. No. 2,605,798 to Boswell discloses a citrus fruit peeler including a pair of abrading rollers and an auger screw which advances the citrus along the rollers.
Along these lines, U.S. Pat. No. 3,745,914 to Wallace discloses a single chamber fruit and vegetable peeler including a frame, a plurality of abrasive roller carried by the frame and arranged in an arcuate pattern, and a drive motor and gears coupled to the rollers. The abrasive rollers are provided in lengthwise segments to facilitate replacement of a damaged section without requiring replacement of an entire roller. Action of the rollers advances the fruit or vegetables from an inlet to a discharge. A rinsing system is provided to wash material from the rollers. The vegetables or fruit are subjected to a tumbling action within the peeling chamber. The amount of peeling is controlled by a height of a gate at the discharge.
U.S. Pat. No. 4,519,305 to Vanosdall discloses a similar apparatus wherein an auger extends only partway into the chamber from the discharge. U.S. Pat. No. 5,858,429 also to Wallace discloses a similar apparatus which includes an auger at a feed hopper, and a rotatable tumbler including rotating paddles within the peeling chamber. This patent also discloses a vision analysis system to evaluate the degree of peeling and adjust the various parameters to provide a desired degree of peeling.
U.S. Pat. Nos. 4,237,782 to Bichel and 4,827,836 to Neidigh disclose peeling apparatus wherein the abrasive rollers are driven by individual hydraulic motors. U.S. Pat. No. 5,780,088 to Zittel discloses a peeler that includes individual electric motors to drive each roller. The rollers can be operated at different speeds or in different directions. An auger which extends through the peeling chamber, may also be controlled by an electric motor.
To increase capacity, a dual peeling or washing chamber apparatus was offered by Vanmark Corporation under the model designation Series 2800. The apparatus included two side-by-side chambers wherein the auger screws rotated in a same direction. Accordingly, the abrasive rollers and their associated motors extended around an arc further upward on a same side.
The abrasive rollers typically used for peeling may include removable end shafts which permit removal of the roller for maintenance. Unfortunately, this construction may permit a relatively large degree of motion at the ends of the rollers, thereby causing vibration and limiting higher rotational speed.
Also, the abrasive rollers commonly used for peeling may include a metal surface with a pattern of indentations and protrusions formed therein, or may include sand or other abrasives impregnated in a matrix. Such abrasive surfaces may not provide uniform abrasion, may not wear uniformly, and/or provide sufficient service life.
In view of the foregoing background, it is therefore an object of the invention to provide a peeling apparatus and associated methods including abrasive rollers which are less likely to experience vibration and/or which may last longer in service.
These and other objects, features and advantages in accordance with the present invention are provided by a peeling apparatus which in one embodiment includes a frame, and at least one set of abrasive rollers carried by the frame to define at least one peeling chamber, and wherein at least one abrasive roller comprises an elongate body portion having an abrasive outer surface and a pair of mounting stubs permanently affixed to respective opposing ends of the elongate body portion. This arrangement of the mounting stubs permits greater precision and balancing, and thereby permits higher rotational speeds.
The elongate body portion and the pair of mounting stubs may each comprise metal. Accordingly, the pair of mounting stubs may be welded to respective ends of the elongate body portion to provide the permanent fixation.
The elongate body portion may have a tubular shape, and the abrasive outer surface may comprise a plurality of knurls arranged in a pattern. In some embodiments, at least some of the knurls may comprise a leading edge portion being steeper than a trailing edge portion. Accordingly, greater strength may be provided to reduce wear and thereby increase service life. This particularly advantageous feature of the knurl shape may be used with or independently of the permanently fixed mounting stubs.
At least some of the knurls may have a substantially same shape. The knurls may be integrally formed with the elongate body portion. In other words, the knurls may be formed into or from outer surface portions of the elongate body portion. For additional service life, a surface coating may be applied over the knurls. For example, the surface coating may comprise at least one of cobalt, chromium, tungsten, and nickel, or any other suitable coating. The elongate body portion may comprise at least one of steel and aluminum.
One method aspect of the invention is for making an abrasive roller for a peeling apparatus of a type comprising a frame, and at least one set of abrasive rollers carried by the frame to define at least one peeling chamber. The method preferably comprises providing an elongate body portion, and permanently affixing a pair of mounting stubs to respective opposing ends of the elongate body portion. The elongate body portion and the pair of mounting stubs may each comprise metal, and permanently affixing may comprise welding the metal components together.
Another method aspect of the invention is also for making an abrasive roller for a peeling apparatus including a frame, and at least one set of abrasive rollers carried by the frame. The method may comprise providing an elongate body portion comprising comprising at least one of steel and aluminum, forming a plurality of knurls on the elongate body portion in a pattern defining an abrasive outer surface, and forming an outer coating on the abrasive surface, wherein the coating comprises at least one of cobalt, chromium, tungsten, and nickel.
Yet another method aspect of the invention is also for making an abrasive roller for a peeling apparatus of a type comprising a frame, and at least one set of abrasive rollers carried by the frame to define at least one peeling chamber. The method preferably comprises providing an elongate body portion; and forming a plurality of knurls on the elongate body portion to define an abrasive surface, with at least some of these knurls having a leading edge portion being steeper than a trailing edge portion.